High on the Suspect List:
* Crankshaft Position Sensor (CKP): This sensor tells the computer where the crankshaft is in its rotation cycle. As it gets hot, a faulty CKP sensor can fail to send a signal, causing the engine to die. They are relatively inexpensive to replace. This is a very common cause of this type of problem, especially in older vehicles.
* Ignition Control Module (ICM): The ICM controls the ignition system. Heat can cause it to malfunction. Similar to the CKP, it'll often work fine when cool but fail when hot.
* Ignition Coil: While less likely than the CKP or ICM, a failing ignition coil can also cause intermittent stalling, especially when heat-stressed.
* Fuel Pump Relay: It's possible the relay is failing intermittently when it gets hot. This would cause the fuel pump to stop, leading to the engine dying. These are relatively inexpensive to replace and easy to test with a multimeter.
Less Likely, but Possible:
* Fuel Pump: A weak fuel pump might struggle to maintain pressure when hot. A pressure test is necessary to confirm this.
* Wiring Harness: A short or damaged wire in the ignition system, especially one that experiences heat buildup, can cause intermittent problems. This is difficult to diagnose without careful inspection.
* Mass Airflow Sensor (MAF): While less common for this symptom, a failing MAF sensor can cause erratic running and stalling, but this is usually less tied directly to heat.
Troubleshooting Steps:
1. Check for Trouble Codes: Use an OBD-II scanner (if your truck has it; 1996 might be on the cusp) to read any diagnostic trouble codes (DTCs). This could pinpoint the problem. If no OBDII, you might need a scanner specific to your year Ford truck.
2. Check the CKP Sensor: This should be your first target. It's relatively easy to access and replace. Look for overheating or damage.
3. Inspect the ICM: Visually inspect the ICM for any signs of damage or overheating.
4. Check the Ignition Coil: Look for cracks or obvious signs of damage. Testing an ignition coil requires specialized equipment.
5. Check Fuel Pressure: If you suspect a fuel delivery problem, you'll need a fuel pressure gauge to test the fuel system's pressure.
6. Test the Fuel Pump Relay: A simple multimeter test can determine if the relay is working properly.
7. Listen Carefully: When it stalls, listen closely. Does it sputter and die, or does it just cut off abruptly? This can provide clues.
Important Note: Since this is an older vehicle, some parts may be more difficult to find. It's essential to find parts specifically designed for your 1996 F250 460 engine.
You may need to take it to a mechanic experienced with older Ford trucks if you are not comfortable with automotive diagnostics and repair. This will prevent you from accidentally making the problem worse. The heat-related nature of the problem strongly suggests an electrical or sensor issue.
